This invention relates to variable displacement cylindrical pumps or motors, and while the invention is subject to a wide range of applications, it will be particularly described as applied to a variable delivery pump.
The present invention is an improvement over the system disclosed for journalling trunnions of a cam plate in the prior Budzich U.S. Pat. No. 3,093,081 granted June 11, 1963 and assigned to the same assignee as the present invention. In this patent, and in general practice, variable delivery is provided by a cam plate having trunnions supported along an axis normal to and intersecting an axis of rotation of the main shaft of the pump. Seats for trunnion bearings are provided in machined through openings at opposite sides of a pump casing, these openings being accurately machined to provide a proper fit for trunnion bearings or trunnion pins in order to prevent vibration of the cam plate. It is necessary that these openings be sealed with plugs and/or O-rings to prevent leakage of fluid. The original installation and maintenance of these seals and plugs, and the cost of machining the openings is expensive.
An object of the present invention is to provide a variable displacement cylindrical pump which substantially simplifies the described prior art arrangements.
Another object of the present invention is to provide a variable displacement cylindrical pump wherein no through openings are required in a pump casing for journalling a cam plate.
Other objects, purposes and characteristic features of the present invention will be in part obvious from the accompanying drawings and in part pointed out as the description progresses.